Progress 08/01/08 to 06/03/09
Outputs
Progress Report Objectives (from AD-416) Develop safe and effective biological control agents of Hydrilla. Approach (from AD-416) Risk assessment analysis will be conducted in quarantine to determine suitability for safe biological control introductions. Suitability will be determined through feeding/oviposition/developmental trials on related North American plant species. Significant Activities that Support Special Target Populations Relates to inhouse objective 1: Discover natural enemies of invasive weeds. Invasive weeds invade the Everglades ecosystem decreasing its biodiversity. Biological controls of these weeds will be developed by the introduction of safe insects that reduce their vigor. This project sponsors foreign surveys for new agents of the submersed aquatic weed, hydrilla. Activities were monitored by email, phone calls, and sight visits. Exploratory surveys and research on biological control agents of Hydrilla verticillata (hydrilla) regained momentum in the second half of 2008/2009 when the prolonged drought in Australia was broken. Previously it had been very difficult to collect from sites near Brisbane in Southeast Queensland and field collected hydrilla had been of poor quality, directly impacting the viability of quarantine cultures of potential biological control agents from Thailand, China and Indonesia. During the year, exploratory surveys were conducted in Western Australia, Sarawak and Sabah in Malaysian Borneo and in Guangxi, China. Two trips were conducted to central and southern China to supervise the exploration program being conducted at the Chinese Academy of Sciences (CAS) in Wuhan. Sufficient weevil numbers were generated for laboratory host-range testing and underwater development studies of one Thai weevil species, B. indistinctus. A new Bagous weevil was collected from Western Australia. The adults are much larger than other Bagous collected from hydrilla, though adults have oviposited in hydrilla stems. The defoliating moth from Indonesia, Paracymoriza vagalis, is particularly sensitive to hydrilla quality. The colony decreased with each subsequent generation and insufficient numbers were produced for further testing. Insufficient pupae were available to continue the colony, though poor emergence and lack of male/female synchronization led to the failure of the culture. Representative specimens of Bagous from our field surveys were separated by specimens, three species from Thailand, B. indistinctus, B. latepunctatus, and B. vicinus, and two species from China, B. chinensis and an undescribed species. A third undescribed species from China was also found in the collection; collected in 1994 from hydrilla at a site near Beijing. Early in 2008, larval specimens of the aquatic moth Parapoynx diminutalis from Asia and the Americas were sent for sequencing at the Department of Primary Industries in Brisbane. Results indicate that there are significant sequence differences that indicate population differences across the native and introduced ranges of this insect. However, they all appear to be the same species and host range is unlikely to vary. A new species of moth whose larvae defoliate hydrilla was collected from Western Australia and will be sent to taxonomists for identification. Specimens of Hydrellia flies from Singapore whose larvae mine the leaves of hydrilla was sent to the Smithsonian Institution for identification. These flies have proven to be damaging in culture in South Africa where PPRI are testing several insects for their potential as biological control agents.
Impacts
(N/A)
Publications
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